Cleaning rod. It's a bit long for pistols, so I'm going to assume it's missing some of the extension poles to make it the right length for a rifle/shotgun.

Might be from a specific rifle, but also might just be an aftermarket one.

You just shove some gauze/bit of cloth into the hole at the tip, put your cleaner/oil of choice on it and shove it down the barrel. Repeat until it comes back clean. This one looks steel, so you'd want to be a bit careful so you don't damage the chamber/crown/rifling.